Flame Safety Lamp in Underground Coal Mines. ~ MINING TECHNOLOGY

INTRODUCTION:-

A miner working under conditions of insufficient light over long periods not only impairs his efficiency but also develops an eye disease know a s Nystagmus. Before the invention of miner's flame safety lamp naked lights are used in coal and metal mines. Now a days electric caps lamps are used by every underground workers in coal mines and in a number of metal mines thought naked lights continue to be used some small metal mines. Flame safety lamps are used by supervisory staff in underground coal mines or detection of methane gas.

A flame safety lamp provides light in a mine without danger of igniting inflammable gas and,in the hands of trained workers, it is also a handy and a very convenient device of detecting the presence as well as percentage of firedamp. The purpose of using flame safety lamp is to check the presence of methane, oxygen deficiency, presence of black damp and produces light.

The flame safety lamp is manufactured by J.K and Sons are sold under the trade name velox.

The company, J.K and Sons, manufactures three types of gas testing flame safety lamp. These are as follows:

G.L.-5
G.L.-50
G.L.-60

Of these G.L.-5 is used for accumulation test and other two are used for percentage test.

The three lamps differ from one another in some constructional details.

SECTIONS AND PARTS OF A FLAME SAFETY LAMP.

G.L.-50 consists of three separable sections which can be screwed together for complete assembly and use. Now a days this flame safety lamp is used in mines.

A flame safety lamp has three sections .These are as follows:

Lower Section: This comprises fuel vessel fitted with a burner, a round wick passing through burner, side oil filling arrangements, and a screw spindle flame adjustment device. The oil vessel has ratchet teeth at the top and provision for magnetic locking.

Middle Section with partly Upper Section:This consists of composite lower flange which is screwed on the fuel vessel and a composite middle ring assembled with five steel rods to provide bonnet and chimney at top. The steel rods connecting the lower flange and the middle rings also protect the glass.separate air inlet and outlet ports are provided to avoid mixing of fresh inlet air with gases of combustion. this improves air circulation and results in sharp reactions of methane gas with the flame. There is only one cylindrical thick toughened glass which forms the part of the middle section. During assembly the glass is provided with lower gaskets at the lower end, and also at the upper end below the outer wire gauze. the asbestos gaskets make the glass assembly air tight at the top and at the bottom and should never be omitted during assembly.

The Upper Section: This consists of a bonnet and chimney with hood provision of top feed device, i.e. for enabling mine air roof to enter the lamp from the top.it also has two wire gauzes .

Parts of the flame safety lamp:

Carrying handle: It is used to hold the flame safety lamp at knee height.
Vent Holes or Outlet Holes: It is used to exhaust the combustion gas from safety lamp to the outside.
Bonnet: it is used to protect the wire gauge from damage due to external hit.it also helps protect the flame against high air velocity.
Pillars: There are 5 numbers of pillars are present in flame safety lamp.It helps the bonnet to rest on pillars and protects the glass from external hit.The diameter of the glass is 5 mm.
Snuffer Tube: If the fire is not extinguised after its test or use then, it will totally extinguised by the snuffer tube while opening the lower base of the flame safety lamp as the fired wick will pass through it having low oxygen from outside.
Magnetic Lock: The safety lamp is securely locked when it is use. It should be checked in every 6 months.
Wire Gauze: The function of the gauze is to prevent the passage of flame from interior of lamps thus ensuring safety against explosion of surrounding atmosphere.It consist of two gauzes .one is inner gauze and other is outer gauze. The height of the outer Gauze is 4.5 inch and inner gauze is 4 inch. The radiating area of outer wire is 115 sq.cm and that of inner gauze is 90 sq.cm. The distance between both the gauzes is 1.5 cm.
Asbestos Ring: There two asbestos ring present at the top and bottom of the glass of the flame safety lamp.these are put to make the joints leak proof and prevent the explosion flame to come outside.The outer diameter of each ring is 57 mm and inner diameter of each ring is 47 mm. The width of each ring is 5 mm.
Glass: It protects the flame against high air velocity. The height of the glass is 54 mm. The diameter of the glass is 57 mm. The thickness of the glass is 5 mm.
Glass Retainer: A threaded annular ring which when screwed in holds the outer glass wire gauze and combustion chimney in position.
Wick Retainer: It keeps the wick holder in position.
Wick and Wick Holder: the wick passes through the wick holder. The diameter of the round wick is 6 mm.
Non-Spill Type Oil Valve: It is used for filling oil in the vessel.
Wick Adjuster: The flame height can be regulated by this pointer without opening the lamp.
Oil Vessel: It act as oil reservoir. Its capacity is 70-80 gms.

HOW TO OPEN A FLAME SAFETY LAMP

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